The use of Near Field Communication (NFC) is becoming common place in applications such as contactless payment systems, security access systems, etc. A typical NFC based system consists of a NFC reader Point of Sale terminal) and a NFC device, typically a NFC enabled card or a mobile phone.
Furthermore, a NFC device typically can be configured for either passive load modulation (PLM) or active load modulation (ALM). While, ALM is typically more complex than PLM, components for implementing ALM in a transponder (e.g., a mobile device) can be more compact and, because the transponder utilizes a power source to generate a magnetic field rather than just modulate a magnetic field created by a reader, an ALM transponder can have greater communication distance than a PLM transponder.
In order to perform a transaction using a NFC enabled device and a NFC reader, the NFC enabled device is brought near the NFC reader. The communication between the NFC enabled device and the NFC reader may fail if the NFC reader fails to properly demodulate the signal from the NFC enabled device. Such failures may occur if the NFC enabled device is not properly aligned with the NFC reader or if the NFC enabled device is not within a certain distance range from the NFC reader.
Such failures and other issues can be significantly reduced if there is tuning of the phase for active load modulation (ALM) in a NFC enabled device. Furthermore, there is a need to be able to calibrate the phase in production testing and handling. Therefore, it is desirable to have methods and systems to calibrate phase supported by factory trim data.